1. Field of the Invention
This invention relates to pipeline pigs for use in filling or emptying pipelines, for efficient cleaning of the interior of pipelines, for internal corrosion control and for fluid separation and gathering.
2. Description of the Prior Art
The use of apparatus for moving by fluid flow in the interior of a pipeline, the apparatus being generally known as a pipeline "pig", is commonly employed in industry. Pipeline pigs perform a wide range of useful functions. They are employed during the construction of pipelines as well as during the operational life of pipelines. Pipeline pigs may be run on a one-time or special purpose basis or on a periodic schedule. Pigs are essential for effectively filling or emptying of pipelines, for efficient cleaning, for internal corrosion control, and for fluid separation and gathering.
For general information as to the application and use of pipeline pigs, reference may be had to an article entitled: "Fundamentals of Pipeline Pigging", authored by Burt VerNooy, appearing in Pipeline Industry, September/October 1980, published by the Gulf Publishing Company, Houston, Tex.
For additional background relating to pipeline pigs of the type to which the present invention pertains, reference may be had to the following prior issued U.S. patents:
Novotny--U.S. Pat. No. 646,545 PA1 Bergesen, Jr.--U.S. Pat. No. 1,392,105 PA1 Ford--U.S. Pat. No. 1,713,895 PA1 Smith--U.S. Pat. No. 2,276,109 PA1 VerNooy--U.S. Pat. No. 2,909,796 PA1 Muirhead--U.S. Pat. No. 3,939,519 PA1 Curtis--U.S. Pat. No. 4,083,074 PA1 Krouse et al.--U.S. Pat. No. 4,178,649
The present invention is intended to accomplish the same purpose as pipeline pigs in current use in the pipeline industry, but is distinguished over the prior art in the provision of an improved unitary construction wherein the body and cup portions are integrally formed of a non-metallic material such as natural or synthetic rubber or plastic. The pipeline pig of this invention is particularly adaptable for construction of urethane.
The invention provides a highly effective and yet simple and inexpensive pig for use in pipelines having improved means of effectively sealing the interior of the pipeline by the outwardly extending cups but in an arrangement wherein the pig is flexible and is capable of negotiating relatively sharp turns while at the same time providing a pig of inherent strength and effectiveness.